CVE-2016-0189

CVE-2016-0189 is a memory corruption flaw (out-of-bounds write, per CWE-787) in Microsoft's JScript 5.8 and VBScript 5.7/5.8 scripting engines, as used in Internet Explorer 9 through 11 and other products that embed those engines. It is triggered remotely when a user is lured into viewing a crafted website that mishandles script, corrupting memory in the browser process. A successful attacker gains arbitrary code execution in the context of the current user (or can crash the browser, causing denial of service), with no authentication required but user interaction needed. Anyone running Internet Explorer 9-11 on Windows, or other products using the affected scripting engines, was exposed. Exploitation is well established: public write-ups document its use in drive-by exploit kit attacks and subsequent 'God Mode' local privilege-escalation variants, it is listed in CISA KEV (added 2022-03-28) with known ransomware use, and EPSS assigns a 94.1% probability of exploitation within 30 days.

What to do: Apply the vendor-supplied Microsoft security updates for Internet Explorer and the JScript/VBScript scripting engines per CISA's required action, prioritizing endpoints used for web browsing and email since this is delivered via drive-by website attacks and is known to be used by ransomware operators. Systems that no longer receive updates for IE 9-11 should be migrated to a supported browser or OS. Check your environment against CISA KEV to confirm remediation status.